Hi Rafael,
This is Bogdan from Romania.
I'm a mechanical engineer - specialized in the industrial robotic field, 3D designer and modeler (from time to time and some projects I could make the functional prototype too).
I'm doing product design, industrial design, reverse engineering, ideation, etc.
I have over 15 years experience working on various systems/devices across multiple industries, from concept to launch.
1 - you have to decide what to be... a trike or a quad - there are huge differences between these two
2 - do you have any drawings, sketches?...
4 - which design style do you like most?... don't say wazuma (that is a monster :) )...
5 - do you know what suspension, transmission, motor, gearbox, wheels, breaks, etc, etc to be used?...
a lot more details to be discussed in chat...
as you are aware (for sure), the price should be discussed/negotiated based on the complexity...
Regards
Bogdan